1 | /* |
2 | * Copyright (C) 2017 Apple Inc. All rights reserved. |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions |
6 | * are met: |
7 | * 1. Redistributions of source code must retain the above copyright |
8 | * notice, this list of conditions and the following disclaimer. |
9 | * 2. Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
14 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
15 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
16 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
17 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
18 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
19 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
20 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
21 | * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
23 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
24 | */ |
25 | |
26 | #include "config.h" |
27 | #include "B3EnsureLoopPreHeaders.h" |
28 | |
29 | #if ENABLE(B3_JIT) |
30 | |
31 | #include "B3BasicBlockInlines.h" |
32 | #include "B3BlockInsertionSet.h" |
33 | #include "B3NaturalLoops.h" |
34 | #include "B3ProcedureInlines.h" |
35 | #include "B3ValueInlines.h" |
36 | |
37 | namespace JSC { namespace B3 { |
38 | |
39 | bool (Procedure& proc) |
40 | { |
41 | NaturalLoops& loops = proc.naturalLoops(); |
42 | |
43 | BlockInsertionSet insertionSet(proc); |
44 | |
45 | for (unsigned loopIndex = loops.numLoops(); loopIndex--;) { |
46 | const NaturalLoop& loop = loops.loop(loopIndex); |
47 | |
48 | Vector<BasicBlock*, 4> outOfBodyPredecessors; |
49 | double totalFrequency = 0; |
50 | for (BasicBlock* predecessor : loop.header()->predecessors()) { |
51 | if (loops.belongsTo(predecessor, loop)) |
52 | continue; |
53 | |
54 | outOfBodyPredecessors.append(predecessor); |
55 | totalFrequency += predecessor->frequency(); |
56 | } |
57 | |
58 | if (outOfBodyPredecessors.size() <= 1) |
59 | continue; |
60 | |
61 | BasicBlock* = insertionSet.insertBefore(loop.header(), totalFrequency); |
62 | preHeader->appendNew<Value>(proc, Jump, loop.header()->at(0)->origin()); |
63 | preHeader->setSuccessors(FrequentedBlock(loop.header())); |
64 | |
65 | for (BasicBlock* predecessor : outOfBodyPredecessors) { |
66 | predecessor->replaceSuccessor(loop.header(), preHeader); |
67 | preHeader->addPredecessor(predecessor); |
68 | loop.header()->removePredecessor(predecessor); |
69 | } |
70 | |
71 | loop.header()->addPredecessor(preHeader); |
72 | } |
73 | |
74 | if (insertionSet.execute()) { |
75 | proc.invalidateCFG(); |
76 | return true; |
77 | } |
78 | |
79 | return false; |
80 | } |
81 | |
82 | } } // namespace JSC::B3 |
83 | |
84 | #endif // ENABLE(B3_JIT) |
85 | |
86 | |